As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PHX - ABORTED TAKEOFF - FLT 0511 - EN ROUTE FROM PHX TO OMA THE TAKEOFF WARNING HORN SOUNDED WHEN THROTTLES WERE ADVANCED, REJECTED TAKEOFF. PILOT NOTED SPEED BRAKE WAS POSSIBLY NOT IN FULL DOWN POSITION. MAINTENANCE REMOVED AND REPLACED SPEED BRAKE TAKEOFF WARNING SWITCH (S651) AT TOP LT FORWARD POSITION ON CONTROL STAND IN COCKPIT IAW 31-26-26, OPERATIONAL CHECK WAS GOOD.